/* ============================================================
   nicheng.net — shared design system
   Brand: violet → teal, playful, rounded, airy
   ============================================================ */

@import url('https://fonts.googleapis.com/css2?family=Plus+Jakarta+Sans:ital,wght@0,400;0,500;0,600;0,700;0,800;1,500&family=Space+Grotesk:wght@500;600;700&family=JetBrains+Mono:wght@400;500&display=swap');

/* ---------- Tokens ---------- */
:root {
  --violet: #6D28D9;
  --violet-2: #9061F0;
  --teal: #0D9488;
  --teal-2: #2DD4BF;
  --pink: #EC4899;

  --ink: #1A1430;
  --ink-soft: #48405F;
  --muted: #7A7090;
  --hairline: #E9E4F3;
  --bg: #FAF8FF;
  --card: #FFFFFF;
  --tint: #F3EEFC;

  --grad-brand: linear-gradient(135deg, var(--violet), var(--violet-2));
  --grad-text: linear-gradient(100deg, var(--violet) 5%, #7c3aed 35%, var(--teal) 95%);
  --grad-teal: linear-gradient(135deg, var(--teal), var(--teal-2));
  --grad-pink: linear-gradient(135deg, var(--pink), #f472b6);

  --r-card: 18px;
  --r-ctl: 11px;
  --r-pill: 999px;

  --sh-sm: 0 1px 2px rgba(40, 20, 80, .05), 0 2px 8px rgba(70, 40, 130, .05);
  --sh-md: 0 4px 14px rgba(70, 40, 130, .08), 0 1px 3px rgba(40, 20, 80, .06);
  --sh-lg: 0 18px 50px -16px rgba(80, 50, 150, .28), 0 6px 18px rgba(70, 40, 130, .08);
  --sh-glow: 0 10px 36px -8px rgba(109, 40, 217, .35);

  --font-head: 'Plus Jakarta Sans', system-ui, sans-serif;
  --font-body: 'Plus Jakarta Sans', system-ui, sans-serif;
  --font-mono: 'JetBrains Mono', ui-monospace, monospace;

  --maxw: 1120px;
  --nav-h: 68px;
}

html[data-theme="dark"] {
  --ink: #F4F1FB;
  --ink-soft: #C6BEDC;
  --muted: #948BAD;
  --hairline: #2C2540;
  --bg: #120E1F;
  --card: #1B1530;
  --tint: #221A3A;
  --sh-sm: 0 1px 2px rgba(0,0,0,.3);
  --sh-md: 0 4px 16px rgba(0,0,0,.4);
  --sh-lg: 0 20px 54px -16px rgba(0,0,0,.6);
}

* { box-sizing: border-box; }
html { scroll-behavior: smooth; overflow-x: hidden; }
body {
  margin: 0;
  font-family: var(--font-body);
  background: var(--bg);
  color: var(--ink);
  line-height: 1.6;
  font-size: 16px;
  -webkit-font-smoothing: antialiased;
  text-rendering: optimizeLegibility;
}

/* ---------- Background glows ---------- */
.glow { position: fixed; pointer-events: none; z-index: 0; filter: blur(70px); opacity: .55; border-radius: 50%; }
.glow.violet { width: 540px; height: 540px; top: -200px; left: -160px; background: radial-gradient(circle, rgba(144,97,240,.55), transparent 70%); }
.glow.teal { width: 520px; height: 520px; top: -160px; right: -180px; background: radial-gradient(circle, rgba(45,212,191,.45), transparent 70%); }
html[data-theme="dark"] .glow { opacity: .4; }

/* ---------- Layout ---------- */
.container { max-width: var(--maxw); margin: 0 auto; padding: 0 24px; position: relative; z-index: 1; }
.section { padding: 64px 0; position: relative; z-index: 1; }
.section-sm { padding: 40px 0; }
main { position: relative; z-index: 1; }

/* ---------- Typography ---------- */
h1, h2, h3, h4 { font-family: var(--font-head); font-weight: 800; line-height: 1.1; letter-spacing: -.02em; margin: 0; color: var(--ink); }
h1 { font-size: clamp(2.4rem, 6vw, 4rem); }
h2 { font-size: clamp(1.7rem, 3.5vw, 2.5rem); }
h3 { font-size: 1.25rem; font-weight: 700; }
p { margin: 0 0 1rem; color: var(--ink-soft); }
a { color: var(--violet); text-decoration: none; }
.gt { background: var(--grad-text); -webkit-background-clip: text; background-clip: text; -webkit-text-fill-color: transparent; color: transparent; }
.eyebrow {
  display: inline-flex; align-items: center; gap: 8px;
  font-size: .82rem; font-weight: 600; color: var(--violet);
  background: var(--tint); border: 1px solid var(--hairline);
  padding: 7px 15px; border-radius: var(--r-pill); margin-bottom: 22px; white-space: nowrap;
}
.eyebrow .dot { width: 7px; height: 7px; border-radius: 50%; background: var(--grad-brand); box-shadow: 0 0 0 4px rgba(144,97,240,.18); }
.subhead { font-size: clamp(1.05rem, 1.6vw, 1.25rem); color: var(--muted); max-width: 56ch; }
.lead { font-size: 1.05rem; color: var(--ink-soft); }
.sec-label { font-size: .82rem; font-weight: 700; letter-spacing: .12em; text-transform: uppercase; color: var(--teal); }

/* ---------- Nav ---------- */
.nav {
  position: sticky; top: 0; z-index: 100;
  background: color-mix(in srgb, var(--bg) 78%, transparent);
  backdrop-filter: saturate(1.4) blur(16px);
  border-bottom: 1px solid var(--hairline);
}
.nav-inner { display: flex; align-items: center; gap: 18px; height: var(--nav-h); max-width: var(--maxw); margin: 0 auto; padding: 0 24px; }
.brand { display: flex; align-items: center; gap: 11px; font-family: var(--font-head); font-weight: 800; font-size: 1.12rem; color: var(--ink); letter-spacing: -.02em; flex-shrink: 0; }
.logo-tile {
  width: 38px; height: 38px; border-radius: 11px; background: var(--grad-brand);
  display: grid; place-items: center; color: #fff; font-weight: 800; font-size: 1.15rem;
  box-shadow: var(--sh-glow); flex-shrink: 0;
}
.brand .tld { color: var(--muted); font-weight: 600; }
.nav-links { display: flex; align-items: center; gap: 2px; margin-left: 10px; flex: 1; overflow: visible; }
.nav-link {
  font-size: .92rem; font-weight: 600; color: var(--ink-soft); padding: 8px 13px; border-radius: 9px;
  white-space: nowrap; transition: background .15s, color .15s;
}
.nav-link:hover { background: var(--tint); color: var(--ink); }
.nav-link.active { color: var(--violet); background: var(--tint); }
.nav-right { display: flex; align-items: center; gap: 10px; margin-left: auto; flex-shrink: 0; }

/* language dropdown */
.lang { position: relative; }
.lang-btn {
  display: inline-flex; align-items: center; gap: 7px; font-family: var(--font-body);
  font-size: .9rem; font-weight: 600; color: var(--ink); background: var(--card);
  border: 1px solid var(--hairline); border-radius: var(--r-ctl); padding: 9px 13px; cursor: pointer;
  min-height: 44px;
}
.lang-btn:hover { border-color: var(--violet-2); }
.lang-btn .chev { transition: transform .2s; color: var(--muted); }
.lang.open .chev { transform: rotate(180deg); }
.lang-menu {
  position: absolute; top: calc(100% + 8px); right: 0; min-width: 190px;
  background: var(--card); border: 1px solid var(--hairline); border-radius: 14px;
  box-shadow: var(--sh-lg); padding: 6px; display: none; z-index: 200;
}
.lang.open .lang-menu { display: block; animation: pop .16s ease; }
.lang-menu button {
  display: flex; width: 100%; align-items: center; gap: 10px; font-family: var(--font-body);
  font-size: .92rem; font-weight: 500; color: var(--ink); background: none; border: none;
  padding: 9px 11px; border-radius: 9px; cursor: pointer; text-align: left;
}
.lang-menu button:hover { background: var(--tint); }
.lang-menu button.sel { color: var(--violet); font-weight: 700; }
.lang-menu button .flag { font-size: 1.05rem; }
.lang-menu button .tick { margin-left: auto; color: var(--violet); opacity: 0; }
.lang-menu button.sel .tick { opacity: 1; }

.hamburger { display: none; background: var(--card); border: 1px solid var(--hairline); border-radius: var(--r-ctl); width: 44px; height: 44px; cursor: pointer; place-items: center; color: var(--ink); }

/* ---------- Buttons ---------- */
.btn {
  display: inline-flex; align-items: center; justify-content: center; gap: 9px;
  font-family: var(--font-head); font-weight: 700; font-size: 1rem; cursor: pointer;
  border-radius: var(--r-ctl); padding: 13px 24px; border: 1px solid transparent;
  min-height: 48px; transition: transform .12s, box-shadow .18s, background .18s; text-decoration: none; white-space: nowrap;
}
.btn:active { transform: translateY(1px); }
.btn-primary { background: var(--grad-brand); color: #fff; box-shadow: var(--sh-glow); }
.btn-primary:hover { box-shadow: 0 14px 40px -8px rgba(109,40,217,.5); transform: translateY(-1px); }
.btn-ghost { background: var(--card); color: var(--ink); border-color: var(--hairline); box-shadow: var(--sh-sm); }
.btn-ghost:hover { border-color: var(--violet-2); color: var(--violet); }
.btn-lg { font-size: 1.08rem; padding: 16px 30px; min-height: 56px; }
.btn-block { width: 100%; }

/* ---------- Pills / toggles ---------- */
.pill-row { display: flex; flex-wrap: wrap; gap: 9px; }
.pill {
  display: inline-flex; align-items: center; gap: 7px; font-weight: 600; font-size: .92rem;
  color: var(--ink-soft); background: var(--card); border: 1px solid var(--hairline);
  padding: 9px 16px; border-radius: var(--r-pill); cursor: pointer; min-height: 42px;
  transition: all .15s; text-decoration: none; user-select: none; white-space: nowrap;
}
.pill:hover { border-color: var(--violet-2); color: var(--ink); transform: translateY(-1px); }
.pill.sel { background: var(--grad-brand); color: #fff; border-color: transparent; box-shadow: var(--sh-glow); }
.pill.sel:hover { color: #fff; }

/* ---------- Cards ---------- */
.card { background: var(--card); border: 1px solid var(--hairline); border-radius: var(--r-card); box-shadow: var(--sh-md); }
.tool-shell { padding: clamp(20px, 3vw, 34px); }

/* ---------- Home: tool grid ---------- */
.tool-grid { display: grid; grid-template-columns: repeat(3, 1fr); gap: 18px; }
.tool-card {
  display: block; background: var(--card); border: 1px solid var(--hairline); border-radius: var(--r-card);
  padding: 24px; box-shadow: var(--sh-sm); transition: transform .16s, box-shadow .2s, border-color .2s; color: inherit; position: relative; overflow: hidden;
}
.tool-card:hover { transform: translateY(-4px); box-shadow: var(--sh-lg); border-color: transparent; }
.tool-ico {
  width: 52px; height: 52px; border-radius: 14px; display: grid; place-items: center;
  font-size: 1.5rem; color: #fff; margin-bottom: 16px; box-shadow: var(--sh-md);
}
.ico-violet { background: var(--grad-brand); }
.ico-teal { background: var(--grad-teal); }
.ico-pink { background: var(--grad-pink); }
.tool-card h3 { margin-bottom: 5px; }
.tool-card p { font-size: .92rem; margin: 0; color: var(--muted); }
.tool-card .arrow { position: absolute; top: 24px; right: 22px; color: var(--muted); opacity: 0; transform: translateX(-4px); transition: all .2s; }
.tool-card:hover .arrow { opacity: 1; transform: translateX(0); color: var(--violet); }

/* ---------- Result chips ---------- */
.results-grid { display: grid; grid-template-columns: repeat(4, 1fr); gap: 12px; }
.chip {
  position: relative; background: var(--card); border: 1.5px solid var(--hairline); border-radius: 14px;
  padding: 16px 16px 15px; cursor: pointer; transition: transform .14s, box-shadow .18s, border-color .18s;
  min-height: 64px; display: flex; flex-direction: column; justify-content: center;
}
.chip:hover { transform: translateY(-3px); border-color: var(--violet-2); box-shadow: var(--sh-md); }
.chip .chip-text { font-family: var(--font-head); font-weight: 700; font-size: 1.05rem; color: var(--ink); padding-right: 26px; word-break: break-word; }
.chip .chip-copy { position: absolute; right: 13px; bottom: 12px; color: var(--muted); opacity: 0; transition: opacity .15s; }
.chip:hover .chip-copy { opacity: .8; }
.chip .heart {
  position: absolute; top: 9px; right: 9px; width: 30px; height: 30px; border-radius: 9px;
  display: grid; place-items: center; cursor: pointer; color: var(--muted); background: transparent; border: none;
  transition: all .15s; z-index: 2;
}
.chip .heart:hover { background: var(--tint); color: var(--pink); }
.chip.saved .heart { color: var(--pink); }
.chip.saved { border-color: color-mix(in srgb, var(--pink) 40%, var(--hairline)); }
.chip.copied { border-color: var(--teal); }
.chip.copied::after {
  content: "Copied!"; position: absolute; inset: 0; display: grid; place-items: center;
  background: var(--grad-teal); color: #fff; font-weight: 700; border-radius: 12px; animation: fadeflash 1s ease;
}

/* ---------- Options row ---------- */
.opt-row { display: flex; flex-wrap: wrap; align-items: center; gap: 22px; }
.opt { display: flex; align-items: center; gap: 11px; }
.opt label { font-weight: 600; font-size: .92rem; color: var(--ink-soft); }
.opt .val { font-family: var(--font-mono); font-weight: 500; color: var(--violet); background: var(--tint); padding: 2px 9px; border-radius: 7px; font-size: .85rem; min-width: 30px; text-align: center; }
input[type="range"] { -webkit-appearance: none; appearance: none; height: 6px; width: 150px; border-radius: 99px; background: var(--hairline); outline: none; }
input[type="range"]::-webkit-slider-thumb { -webkit-appearance: none; width: 20px; height: 20px; border-radius: 50%; background: var(--violet); cursor: pointer; box-shadow: var(--sh-glow); border: 3px solid #fff; }
input[type="range"]::-moz-range-thumb { width: 18px; height: 18px; border-radius: 50%; background: var(--violet); cursor: pointer; border: 3px solid #fff; }
.check { display: inline-flex; align-items: center; gap: 9px; cursor: pointer; font-weight: 600; font-size: .92rem; color: var(--ink-soft); user-select: none; min-height: 44px; }
.check input { position: absolute; opacity: 0; }
.check .box { width: 22px; height: 22px; border-radius: 7px; border: 1.5px solid var(--hairline); background: var(--card); display: grid; place-items: center; transition: all .15s; }
.check input:checked + .box { background: var(--grad-brand); border-color: transparent; }
.check .box svg { opacity: 0; color: #fff; transition: opacity .15s; }
.check input:checked + .box svg { opacity: 1; }
.check input:focus-visible + .box { box-shadow: 0 0 0 3px rgba(144,97,240,.35); }

/* ---------- Text input ---------- */
.field {
  width: 100%; font-family: var(--font-body); font-size: 1.05rem; color: var(--ink);
  background: var(--card); border: 1.5px solid var(--hairline); border-radius: var(--r-ctl);
  padding: 15px 18px; transition: border-color .15s, box-shadow .15s; min-height: 52px;
}
.field::placeholder { color: var(--muted); }
.field:focus { outline: none; border-color: var(--violet); box-shadow: 0 0 0 4px rgba(109,40,217,.14); }
.field-row { display: flex; gap: 12px; }
.field-row .field { flex: 1; }

/* ---------- Toast ---------- */
.toast {
  position: fixed; left: 50%; bottom: 96px; transform: translateX(-50%) translateY(16px);
  background: var(--ink); color: #fff; font-weight: 600; font-size: .94rem;
  padding: 13px 20px; border-radius: var(--r-pill); box-shadow: var(--sh-lg);
  display: flex; align-items: center; gap: 9px; opacity: 0; pointer-events: none;
  transition: opacity .25s, transform .25s; z-index: 500;
}
.toast.show { opacity: 1; transform: translateX(-50%) translateY(0); }
.toast .tcheck { width: 20px; height: 20px; border-radius: 50%; background: var(--grad-teal); display: grid; place-items: center; flex-shrink: 0; }

/* ---------- Favorites bar ---------- */
.favbar {
  position: sticky; bottom: 0; z-index: 90; background: color-mix(in srgb, var(--card) 90%, transparent);
  backdrop-filter: blur(16px); border-top: 1px solid var(--hairline); box-shadow: 0 -6px 24px rgba(70,40,130,.06);
}
.favbar-inner { display: flex; align-items: center; gap: 14px; max-width: var(--maxw); margin: 0 auto; padding: 12px 24px; }
.favbar .fav-label { display: flex; align-items: center; gap: 8px; font-weight: 700; font-size: .9rem; color: var(--ink); flex-shrink: 0; }
.favbar .fav-label .hicon { color: var(--pink); }
.fav-list { display: flex; align-items: center; gap: 8px; overflow-x: auto; flex: 1; padding: 4px 0; scrollbar-width: thin; }
.fav-empty { color: var(--muted); font-size: .9rem; font-weight: 500; }
.fav-pill {
  display: inline-flex; align-items: center; gap: 7px; background: var(--tint); border: 1px solid var(--hairline);
  border-radius: var(--r-pill); padding: 7px 8px 7px 14px; font-weight: 600; font-size: .88rem; color: var(--ink);
  white-space: nowrap; flex-shrink: 0;
}
.fav-pill .rm { width: 22px; height: 22px; border-radius: 50%; border: none; background: transparent; color: var(--muted); cursor: pointer; display: grid; place-items: center; }
.fav-pill .rm:hover { background: var(--pink); color: #fff; }
.fav-count { background: var(--grad-brand); color: #fff; font-size: .72rem; font-weight: 700; padding: 2px 8px; border-radius: 99px; }

/* ---------- Ad slot ---------- */
.ad-slot {
  border: 1.5px dashed var(--hairline); border-radius: var(--r-card); background: repeating-linear-gradient(135deg, transparent, transparent 11px, var(--tint) 11px, var(--tint) 22px);
  min-height: 110px; display: grid; place-items: center; text-align: center; color: var(--muted);
}
.ad-slot .ad-tag { font-family: var(--font-mono); font-size: .72rem; letter-spacing: .1em; text-transform: uppercase; color: var(--muted); }
.ad-slot.sidebar { min-height: 600px; }

/* ---------- FAQ ---------- */
.faq-item { border-bottom: 1px solid var(--hairline); }
.faq-q { display: flex; align-items: center; justify-content: space-between; gap: 14px; width: 100%; background: none; border: none; padding: 20px 0; cursor: pointer; font-family: var(--font-head); font-weight: 700; font-size: 1.08rem; color: var(--ink); text-align: left; }
.faq-q .pm { flex-shrink: 0; color: var(--violet); transition: transform .2s; }
.faq-item.open .pm { transform: rotate(45deg); }
.faq-a { max-height: 0; overflow: hidden; transition: max-height .28s ease; }
.faq-item.open .faq-a { max-height: 240px; }
.faq-a p { padding-bottom: 20px; margin: 0; color: var(--ink-soft); }

/* ---------- Footer ---------- */
.footer { border-top: 1px solid var(--hairline); padding: 48px 0 120px; margin-top: 40px; }
.footer-grid { display: grid; grid-template-columns: 1.6fr 1fr 1fr 1fr; gap: 32px; }
.footer h4 { font-size: .82rem; text-transform: uppercase; letter-spacing: .1em; color: var(--muted); font-weight: 700; margin-bottom: 14px; }
.footer a { display: block; color: var(--ink-soft); font-weight: 500; font-size: .94rem; padding: 5px 0; }
.footer a:hover { color: var(--violet); }
.footer .tagline { color: var(--muted); font-size: .92rem; max-width: 30ch; margin-top: 12px; }

/* ---------- prose (blog/SEO) ---------- */
.prose { max-width: 720px; }
.prose h2 { font-size: 1.6rem; margin: 38px 0 14px; }
.prose h3 { font-size: 1.2rem; margin: 28px 0 10px; }
.prose p { font-size: 1.05rem; line-height: 1.72; }
.prose ul { padding-left: 22px; color: var(--ink-soft); line-height: 1.7; }
.prose li { margin-bottom: 8px; }
.prose a { font-weight: 600; border-bottom: 1.5px solid color-mix(in srgb, var(--violet) 30%, transparent); }
.prose code { font-family: var(--font-mono); font-size: .86em; background: var(--tint); color: var(--violet); padding: 2px 7px; border-radius: 6px; }
html[data-theme="dark"] .prose code { color: var(--violet-2); }

/* ---------- helpers ---------- */
.tac { text-align: center; }
.mx-auto { margin-left: auto; margin-right: auto; }
.mt-0 { margin-top: 0; }
.stack-sm > * + * { margin-top: 10px; }
.divider { height: 1px; background: var(--hairline); border: 0; margin: 0; }
.grid-2 { display: grid; grid-template-columns: 1fr 1fr; gap: 24px; }
.with-side { display: grid; grid-template-columns: 1fr 300px; gap: 40px; align-items: start; }

@keyframes pop { from { opacity: 0; transform: translateY(-6px) scale(.97); } to { opacity: 1; transform: none; } }
@keyframes fadeflash { 0% { opacity: 0; } 18% { opacity: 1; } 100% { opacity: 1; } }
@keyframes rise { from { transform: translateY(16px); } to { transform: none; } }
@media (prefers-reduced-motion: no-preference) { .rise { animation: rise .55s cubic-bezier(.2,.7,.3,1) both; } }

/* ---------- Responsive ---------- */
@media (max-width: 940px) {
  .tool-grid { grid-template-columns: repeat(2, 1fr); }
  .results-grid { grid-template-columns: repeat(3, 1fr); }
  .footer-grid { grid-template-columns: 1fr 1fr; gap: 28px; }
  .with-side { grid-template-columns: 1fr; }
  .ad-slot.sidebar { min-height: 140px; }
  .nav-links { display: none; }
  .hamburger { display: grid; }
}
@media (max-width: 600px) {
  .container { padding: 0 16px; }
  .section { padding: 44px 0; }
  .tool-grid { grid-template-columns: 1fr; }
  .results-grid { grid-template-columns: repeat(2, 1fr); }
  .grid-2 { grid-template-columns: 1fr; }
  .footer-grid { grid-template-columns: 1fr 1fr; }
  .opt-row { gap: 14px; }
  .favbar-inner { padding: 10px 16px; }
  .nav-inner { padding: 0 16px; gap: 10px; }
  .brand .tld { display: none; }
}

/* ---------- Mobile slide nav ---------- */
.mobile-nav { position: fixed; inset: 0; z-index: 300; display: none; }
.mobile-nav.open { display: block; }
.mobile-nav .scrim { position: absolute; inset: 0; background: rgba(26,20,48,.4); backdrop-filter: blur(2px); }
.mobile-nav .panel { position: absolute; top: 0; right: 0; bottom: 0; width: 280px; max-width: 84vw; background: var(--card); box-shadow: var(--sh-lg); padding: 22px; display: flex; flex-direction: column; gap: 4px; animation: slidein .22s ease; overflow-y: auto; }
.mobile-nav .panel a { font-weight: 600; font-size: 1.05rem; color: var(--ink); padding: 13px 14px; border-radius: 11px; }
.mobile-nav .panel a:hover, .mobile-nav .panel a.active { background: var(--tint); color: var(--violet); }
.mobile-nav .close { align-self: flex-end; background: var(--tint); border: none; width: 40px; height: 40px; border-radius: 11px; cursor: pointer; color: var(--ink); display: grid; place-items: center; margin-bottom: 8px; }
@keyframes slidein { from { transform: translateX(100%); } to { transform: none; } }

/* focus visibility */
:focus-visible { outline: 2px solid var(--violet); outline-offset: 2px; }
.chip:focus-visible, .pill:focus-visible { outline-offset: 3px; }